What’s so great about Urban Living for Birds?
A few years ago, Anders Pape Muller from the University of Paris-Sud walked through the small suburban town of Orsay, France, counting all the birds he saw or heard. He walked through built-up urban areas, and through forest and farmland. He found that Orsay’s birds were congregating largely in the urban zones. He found 77 percent of them within a hundred metres of the nearest house. When he repeated the census in a similar town in Denmark, he found the same thing: 87 percent of local birds were sticking close to humans.
The above paragraph is from an article on Phenomena: A Science Salon website, and the full article is here. It goes on to say that the din of traffic, industry, and crowds can drown out the calls and songs, forcing vocal bird species to change their tune,shout louder, or simply move to the country. But his research suggests that it might protect them from brood parasites such as cuckoos. There are probably other benefits too. Cities provide rich sources of food, and offer safety from predators that are deterred by humans or our domestic pets.
In The Telegraph online there is a great article about the studies that have been going about why certain bird species are urban dwellers, and some not…
A British study, published in Global Change Biology… found no evidence that brainier birds are more likely to live in towns, but it did find three other things that predisposed birds to succeed in urban areas. First and most important, urban birds were more likely to be generalists rather than specialists. Successful urban birds are more likely to be predominantly seed eaters, or at least less likely to depend on insects for food. The third finding was that urban birds are unlikely to nest on or near the ground. The reasons for this are not clear, but there are two possibilities. One is that ground nesters suffer higher levels of predation in towns, especially from cats. The other is that there simply isnt much suitable nesting habitat in towns for ground-nesting birds.
It also says that the Blackbird only moved into our towns in Victorian times. I find I can get much closer to a blackbird in town, than in the countryside – they are used to people-presence aren’t they?
No – that’s not why – according to a study reported in the Mail Online that found swans living in cities tend to be bolder and it is at least partly determined by a gene called DRD4, rather than learnt through more frequent contacts with people.
The researchers approached the birds and calculated how close they could get before they flew away.As expected, they noticed that while rural swans started flying away if a human was closer than 393ft (119 metres), the scientists could push the line further with urban swans, which let them come as close as 128ft (39 metres) before taking off.
It could help to explain why swans in public parks and on urban rivers have a reputation for being so aggressive towards humans – they are simply not afraid of us.
The Young People’s Trust for the Environment says that the three commonest city birds are the starling, sparrow and pigeon. They are three very adaptable species, always ready to exploit a potential food source or a suitable nest site. Of course this then brings in the predators such as the Peregrine Falcon who sees ours tall buildings as cliffs.
Cities are always warmer than the countryside in winter – which can mean the difference between Life and Death – especially for smaller birds that have a much larger surface area compared to their size/ volume and so lose much more body heat than a larger bird
According to biologist Simon Watt, in a guardian article cities represent some of the worlds hotspots for evolution and behavioural adaptation. Speaking at the Cheltenham science festival, Watt cited a host of examples of how the urban environment is prompting new genetic shifts and unexpected behaviours. A proportion of black cap warblers, which used to migrate to Morocco or southern Spain, have shifted their route to Britain where urban heat islands and garden bird feeders allow them to survive at more northerly latitudes than was previously possible. The ones that come to Britain are starting to get shorter wings better for manoeuvrability, worse for long flights and longer beaks, which are better to get through the wee bars of garden bird feeders, although worse for things like fruits and berries.
It’s not all good news for those birds that are living in our towns and cities. Some scientists have found that Great Tits are living shorter lives, when they opt for an Urban Life – and they put this down to stress
Birds are extraordinarily adaptable creatures – and have to be. For example the need to sing louder, even change their song – to be heard over our urban din; and many – because of street lighting but also because our towns and cities are quieter at night – are singing in the night – according to an article in The Independent:
A University of Aberystwyth study, based on birds in 20 British cities, found that great tits sing at a significantly higher pitch in noisy urban areas compared to the countryside.
Research at Sheffield University has shown that urban robins, highly territorial birds that rely on vocal communication, reduce the chances of noise interference by singing during the night in areas that are noisy during the day. They found 18 sites where robins were heard singing nocturnally. At one site, a bird was heard at night but not during the day.
Findings published in the journal Behavioural Ecology suggests the brains of some animals have got bigger in tandem with the industrialisation of their habitat – making some city animals smarter than their rural peers. You can read about this on the Mail Online
One way to help bring in ground-nesting birds, protect chicks from cats and other predators, and to liven up a wall or street is this project I stumbled across online – called The Happy City Birds Project- which is an “ungoing project” (that is not a typo!) that Thomas Dambos began many years ago, which sprung from Thomas being a former graffiti artist, looking for a way to do street art in a positive way that everyone can understand. All of the birdhouses are made from recycled materials. Since 2006 Thomas has made and put up more than 3500 birdhouses in different shapes and colours all over the world. Isn’t that a great idea?
Here are a few other images I have found online: